OBJECTIVETo report the clinical diagnosis, treatment and follow-up of children with holocarboxylase synthetas(HCS) deficiency and explore the gene mutation spectrum of the disease.

METHODSEleven children with HCS deficiency were enrolled. Mass spectrometry analysis and biotinidase activity determination were used for diagnosis of HCS deficiency. HCS gene mutations were analyzed by PCR directed sequencing methods. Ten patients received oral biotin treatment (10-40 mg/d). Clinical effects of biotin treatment were observed.

RESULTSAll 11 cases developed apathetic, lethargy and metabolic acidosis at different degrees, and 10 cases presented with skin lesions. The average blood 3-hydroxyisovaleryl-carnitine concentrations and urinary 3-methylcrontonylglycine and methylcitrate concentrations increased significantly. The biotinidase activity increased, being higher over 30% of the normal reference value. Four mutations in HCS gene were identified, and they were c.1522C>T (R508W), c.1088T>A (V363D), c.126G>T (E42D) and c.1994G>C (R665P) (a new variant) and the frequency was 50%, 29%, 7% and 14% respectively. The symptoms disappeared in 10 cases 1-2 weeks after biotin treatment, and blood and urinary abnormal metabolites were gradually reduced to normal 2-6 months after treatment.

CONCLUSIONSHCS deficiency is characterized by nervous system damage, skin lesions and metabolic acidosis. Mass spectrometry analysis, biotinidase activity determination and gene mutation analysis may be helpful in the definite diagnosis of this disorder. The effect of early biotin treatment is satisfactory. The mutations R508W and V363D might be hot-spots in Chinese children with HCS deficiency.

Biotin ; therapeutic use ; Biotinidase ; metabolism ; Carbon-Nitrogen Ligases ; genetics ; Child, Preschool ; Female ; Holocarboxylase Synthetase Deficiency ; diagnosis ; therapy ; Humans ; Infant ; Infant, Newborn ; Male ; Mutation

Multiple carboxylase deficiency (MCD) includes autosomal recessive holocarboxylase synthetase (HLCS) deficiency and biotinidase (BTD) deficiency, which are caused by and gene mutations respectively. Neonatal screening for HLCS deficiency is based on 3-hydroxyisovaleryl carnitine in dry blood filter paper, and BTD deficiency is based on BTD activity determination. HLCS deficiency and BTD deficiency are characterized by neurocutaneous syndrome and organic aciduria, however, they are different in onset age, neurological symptoms and metabolic decompensation, which needed to be differentiated from acquired biotin deficiency or other genetic metabolic diseases. The diagnosis of the disease requires a combination of biochemical characteristics of hematuria, enzyme activity determination and genetic test. Routine biotin doses are effective for most MCD patients. This consensus is intended to benefit early screening and diagnosis of MCD.
Biotin/therapeutic use* ; Biotinidase Deficiency/therapy* ; Carbon-Nitrogen Ligases/metabolism* ; Consensus ; Holocarboxylase Synthetase Deficiency/genetics* ; Humans ; Infant, Newborn ; Multiple Carboxylase Deficiency/drug therapy* ; Neonatal Screening

OBJECTIVETo confirm the diagnosis of multiple carboxylase deficiency (MCD) on the gene level and explore the mutations in Chinese children with MCD.

METHODSBiotinidase (BT) and holocarboxylase synthetase (HLCS) genes were analyzed by PCR and direct sequencing for the 4 BT deficiency patients and 8 HLCS deficiency patients, respectively. The identified mutations in the parents of the patients and 50 normal controls were screened by PCR-restriction fragment length polymorphism and direct DNA sequencing.

RESULTSTotal detection rate of gene mutation is 100% in the 12 children with MCD. Six mutations were detected in the 4 children with BT deficiency, they were c. 98-104del7ins3, c. 1369G>A (V457M), c. 1157G>A(W386X), c. 1284C>A(Y428X), c. 1384delA and c. 1493_1494insT. The last four were novel mutations. Four mutations were found in the 8 children with HLCS deficiency. They were c. 126G>T (E42D), c. 1994G>C (R665P), c. 1088T>A (V363D) and c. 1522C>T (R508W). The last two were hot-spot mutations [75%(12/16)], and c. 1994G>C (R665P) was a novel mutation.

CONCLUSIONThis study confirmed the diagnosis of 12 patients with MCD on the gene level. Six mutations were found in the BT gene and 4 in the HLCS gene, including 5 novel mutations. Two mutations of the HLCS gene are probably hot-spot mutations in Chinese children with HLCS deficiency.

Asian Continental Ancestry Group ; genetics ; Base Sequence ; Biotinidase ; genetics ; Biotinidase Deficiency ; Carbon-Nitrogen Ligases ; deficiency ; genetics ; Case-Control Studies ; Child ; Child, Preschool ; Female ; Humans ; Infant ; Male ; Molecular Sequence Data ; Multiple Carboxylase Deficiency ; genetics ; metabolism ; Mutation

OBJECTIVETo study the feasibility of using methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) for the detection of DNA methylation in placenta tissue.

METHODSFor blood cells from 13 non-pregnant women and 9 euploid placenta, the ratios of DNA methylation were evaluated for 4 genes including CGI149, CGI113, HLCS and ACTB with MS-MLPA and bisulfite sequencing, respectively.

RESULTSThe methylation ratio of the ACTB gene was 0-0.1 for the blood cells when the digestion control was completely digested. The cutoff value for the methylation ratio of MS-MLPA has been determined as 0.1. For the 9 placenta samples, results of MS-MLPA and bisulfite sequencing were concordant for all of the four genes.

CONCLUSIONMS-MLPA is an effective alternative to bisulfite sequencing for the assessment of methylation ratios in placental tissues.

Actins ; genetics ; Adult ; Carbon-Nitrogen Ligases ; genetics ; CpG Islands ; genetics ; DNA Methylation ; Endosomal Sorting Complexes Required for Transport ; genetics ; Feasibility Studies ; Female ; Humans ; Multiplex Polymerase Chain Reaction ; methods ; Placenta ; metabolism ; Pregnancy ; Reproducibility of Results ; Ribosomal Proteins ; genetics ; Young Adult

High-yield production of HLA-A*0201 heavy chain is a prerequisite to the preparation of HLA-A2 tetramer. The present study was aimed to construct the expression vector of recombinant HLA-A*0201-BSP fusion gene for preparing HLA-A2 tetramers. The extracellular region HLA*0201 was cloned by RT-PCR from HLA-A2(+) donor, and a 15-amino acid biotin-protein ligase (BirA) substrate peptide (BSP) for BirA-dependent biotinylation was added to the COOH-terminus of HLA-A*0201 heavy chain. Then the fusion gene was cloned into pBV220 vector at EcoRI and Bam HI sites and its sequence was confirmed by DNA sequence analysis. The recombinant plasmid pBV220-HLA-A*0201-BSP was transformed to the competent cells of E.coli DH5alpha. The results showed that the HLA-A*0201-BSP fusion protein was successfully expressed in the form of inclusion body and amounted to over 28% of total cell proteins via induction at 42 degrees C. After washed with triton X-100 and urea, the inclusion body was dissolved with 8 mol/L urea and then purified with Sepharcyl S-300 HR, and the final purity reached above 90%. It is concluded that the HLA-A*0201-BSP fusion gene was cloned successfully and expressed efficiently in E.coli DH5alpha. This work establishes a convenient approach for purification of large quantity of recombinant HLA-A*0201-BSP. This provides the basis for the preparation of HLA-A2 tetramers.
Biotin ; biosynthesis ; genetics ; Carbon-Nitrogen Ligases ; biosynthesis ; genetics ; Cloning, Molecular ; Escherichia coli ; genetics ; metabolism ; Escherichia coli Proteins ; biosynthesis ; genetics ; HLA-A Antigens ; biosynthesis ; genetics ; HLA-A2 Antigen ; Humans ; Ligases ; biosynthesis ; genetics ; Recombinant Fusion Proteins ; biosynthesis ; genetics ; Repressor Proteins ; biosynthesis ; genetics ; Substrate Specificity ; Transcription Factors ; biosynthesis ; genetics

HLA-A* 2402 is one of the most frequently encountered HLA-A alleles in East Asian populations. In order to study the CD8+ T cell responses in Chinese populations, we have described the generation and functional test of HLA-A* 2402 tetramer loaded with HCMV pp65(341-349) peptide (QYDPVAALF, QYD). The cDNA of HLA-A* 2402 heavy chain was cloned by RT-PCR from one of the donors. DNA fragment encoding the ectodomain of HLA-A* 2402 heavy chain fused at its carboxyl-terminal a BirA substrate peptide (BSP) was amplified by PCR with the cloned heavy chain cDNA as a template. The wild-type gene of HLA-A* 2402-BSP was not expressed in Escherichia coli (E. coli), while mutant HLA-A* 2402-BSP gene with optimized codons was overexpressed as inclusion bodies in E. coli. Furthermore, the soluble HLA-A* 2402-QYD monomers were generated by in vitro refolding of washed inclusion bodies in the presence of beta2-microglobulin and QYD peptide. The tetramer was subsequently formed by mixing HLA-A* 2402-QYD monomers with streptavidin-PE at a molar ratio of 4:1. Flow cytometry analysis indicated that this tetramer possessed binding activity with specific CTL from HLA-A24+ donors and the frequencies of tetramer-binding CTL were 0.09% - 0.37% within total CD8+ T cells. This tetrameric agent provides a powerful tool to explore the secrets of CTL responses against HCMV antigens in HLA-A* 2402 individuals.
Amino Acid Sequence ; CD8-Positive T-Lymphocytes ; cytology ; metabolism ; Carbon-Nitrogen Ligases ; metabolism ; Electrophoresis, Polyacrylamide Gel ; Escherichia coli ; genetics ; Escherichia coli Proteins ; metabolism ; Flow Cytometry ; Gene Expression ; HLA-A Antigens ; chemistry ; genetics ; metabolism ; HLA-A24 Antigen ; Humans ; Oligopeptides ; genetics ; metabolism ; Phosphoproteins ; chemistry ; genetics ; metabolism ; Protein Multimerization ; Recombinant Fusion Proteins ; chemistry ; genetics ; metabolism ; Repressor Proteins ; metabolism ; Substrate Specificity ; T-Lymphocytes, Cytotoxic ; cytology ; metabolism ; Viral Matrix Proteins ; chemistry ; genetics ; metabolism